The UK will undertake a large-scale study that could see more than 300,000 people tested to find out what proportion of the population has already had coronavirus and how many may have some immunity to it.
The announcement comes as a further 759 people died with the virus in UK hospitals, bringing the total number of deaths to 18,100.
Twenty thousand households in England are being contacted to take part to track coronavirus in the general population.
A number of studies have been launched around the world to work out how widespread the infection is. So far, they have found the proportion of people with antibodies showing they have been infected is low. The World Health Organization said this week it appears that only around 2 to 3% of people in the general population have been infected – with or without symptoms.
The results of the new study will be crucial for planning a strategic endgame to the pandemic in the UK.
Volunteers will provide nose and throat swabs on a regular basis to see whether they have the virus.Over the next year, they will be asked to take further tests every week for the first five weeks, then every month thereafter.
Around 1,000 people will be invited to have a blood test every month to find out whether they have antibodies to the virus.The findings will help to inform the government's strategy for easing the lockdown. Meanwhile, the government's scientific advisers will present their findings to ministers once research has been gathered on whether the public should wear face masks.
Health Secretary Matt Hancock said the research would answer "crucial questions" as policy makers, clinicians and scientists "continue to build up our understanding of this new virus".
Regular testing is part of the strategy to see whether those with antibodies may have some immunity from Covid-19, which might allow them to resume more normal lives. Scientists have warned, however, that even if there is some protection, they do not know how long it will last.
Earlier this month, the government admitted that none of the 3.5 million test kits it had bought from China at a cost of £20m was usable but insisted it was continuing to work with other potential suppliers.
Scientists at Oxford University are in the process of validating an antibody test, also known as an Elisa test, which will be used in this study.
The government has pledged 100,000 tests a day by the end of April. This commitment was reaffirmed during Wednesday’s Prime Ministers Questions by First Secretary of State Dominic Raab.
Wednesday's figures showed 22,814 tests were carried out.
Elsewhere,more than 600,000 volunteers have been approved to help those who are most at risk and isolating during the lockdown, the NHS and Royal Voluntary Service has said.
The government made an appeal last month for volunteers and received an overwhelming response of people wanting to support.Healthcare practitioners, pharmacists, local authority and social care staff have been calling on volunteers to carry out around 35,000 tasks over the past two weeks, including delivering medicines, shopping and other supplies as well as making calls to check in on those isolating at home.